Total ankle replacement (“TAR”) procedures involve replacement of the ankle joint with an artificial implant that is designed to treat a particular condition, such as arthritis or fracture of a bone forming the joint. A conventional TAR procedure may include scanning the damaged foot and leg of the patient with medical imaging machine (e.g., CT machine, MRI machine) while the patient is in a supine position. The individual bones in each of the scans or images of the foot and leg are then segmented. A three-dimensional (“3D”) bone model of the bones is generated from the segmented images, and then the surgeon may plan the surgical procedure using the patient specific 3D bone models. Surgical planning may include determining implant size and position, resection depths and positions relative to the bones, and surgical approaches, among other parameters. Once planning is complete, the surgery is then performed according to the plan.
One particular error-factor in TAR procedures is valid ankle pose estimation during the surgical planning steps of the procedure given the image scans forming the basis of the 3D bone models are not performed under weight bearing conditions. More particularly, the image scans performed on a non-standing, supine patient depict the bones of the foot and leg (e.g., tibia, fibula, talus, calcaneus) in an un-weighted state or condition. That is, the weight of the patient body is not acting on the bones of the leg and foot during the imaging scans. Thus, the 3D models of the bones of the leg and foot are modeled as if the bones are un-weighted. In this way, any surgical planning that takes place based on 3D models does not take into account a standing or weighted position of the bones relative to each other or relative to the floor. This can result in less than desirable surgical outcomes.
Accordingly, there is a need in the art for system and methods that address these shortcomings, among others.